The PMDX-2PARPCI is a modified parallel port card that provides signals that
are equivalent to EPP mode without having to set EPP mode. We did this
because there is no way to use the computer's BIOS to set EPP mode on a
plug-in card, and Mach3 does not try to set EPP mode on plug-in cards. You
do not need to do anything to cause the PMDX-2PARPCI to create signals
compatible with the G540. This is why the modified card was created in
the first place.
The voltages that you are reading on pin 17 are OK. In the real world digital
signals never reach exactly 0 volts or 5 volts, nor do devices connected to
them expect the signals to do so.
The Output1 and Output2 terminals of the G540 are Open Collector outputs.
They expect you to connect a relay or similar device between the output
and a power supply voltage. When the signal turns on, it grounds the output,
thus causing power to flow from the power supply, through your relay, and
back to ground. The G540 output will never source any voltage itself and
if you look at the output with a meter connected from the bare output terminal
and ground you will not see any voltage.
For a description of how this is supposed to work, see "Step 8" on page 4
of the G540 manual, and the diagram on page 8 of the G540 manual.
